1. Field of the Invention
The present invention relates to a heat-dissipating fan. More particularly, the present invention relates to a heat-dissipating fan for effectively lowering noise resulting from tangential wind effect.
2. Description of Related Art
FIG. 1 illustrates a sectional view of a device, which is described in copending U.S. patent application Ser No. 11/272,678, the entire specification of which incorporated herein by reference. The device comprises a heat-dissipating device 10 and a heat-dissipating fan 20. The heat-dissipating device 10 is in direct contact with a heat-generating component for absorbing heat energy. The heat-dissipating fan 20 is mounted above the heat-dissipating device 10 for assisting in dissipation of heat.
The heat-dissipating device 10 includes a central heat-conducting member 11 and a plurality of peripheral fins 12 extending outward from the central heat-conducting member 11. The central heat-conducting member 11 includes a compartment 13 in which a propeller 14 is mounted.
The heat-dissipating fan 20 is mounted on top of the heat-dissipating device 10 in an inverted state. The heat-dissipating fan 20 includes a casing 21 and a base 23 fixedly supported by a plurality of ribs 22 in the casing 21. A stator 24 and a rotor 25 are mounted on the base 23. Magnetic members 26 and 15 are respectively mounted on the rotor 25 and the propeller 14 to provide a mutually attracting effect for allowing synchronous rotation of the rotor 25 and the propeller 14.
However, the heat-dissipating fan 20 in an inverted state generates great noise due to tangential wind effect. More specifically, the ribs 22 for fixing the base 23 must extend across the air inlet area for mounting the heat-dissipating fan 20 in the inverted state. When the rotor 25 rotates and drives air downward, the ribs 22 extending across the air inlet area create a wind barrier and thus generate turbulence, leading to great noise due to tangential wind effect.